Civilisation V was released in 2010 and went on to be a big success story. The franchise has sold over 33 million units over the years with Civilisation V being the best-selling version having sold around 8 million units sold worldwide.
And the gamer reviews for Civilisation V were pretty good too. G5 gave it 5 out of 5. PC Gamer gave it 98 out of 100, and Game Informer 9.75 out of 10. And Civilisation V took the 'Best Strategy Game' award at the 2011 BAFTA Games Awards.
That's not to say there weren't a few gripes with Civilisation V though. One major quibble was the quality of the AI game opponents and their lack of smarts when conducting negotiations and diplomacy.
So how have Firaxis Games tried to improve on the success of Civilisation V?
The latest version, Civilisation VI, is due for release on October 21 2016. The same team that developed Civilisation V have also worked on its successor. And it's already been named 'Best PC Game' and 'Best Strategy Game' at the Game Critics Awards.
So what's new? Well, the developers have suggested in various interviews that research found many gamers had come to find playing Civilisation V one-dimensional.
The big aim with Civilisation VI has been to create a game that makes gamers think on their feet a lot more. A more reactive experience is what the developers have tried to achieve.
And with that in mind they've made some big new changes for Civilisation VI. For a start city development has been overhauled. Now when you've built a city centre you have to specialise the function of that city. It can become a specialist military, industry or science city, say - but it can't contain elements of everything.